A driver carrying a computer that tries to recognise dolphin sounds and generate responses in real time will soon attempt to communicate with wild dolphins off the coast of Florida. If the bid is successful, it will be a big step towards two-way communication between humans and dolphins.

Since the 1960s, captive dolphins have been communicating via pictures and sounds. In the 1990s, Louis Herman of the Kewalo Basin Marine Mammal Laboratory in Honolulu, Hawaii, found that bottlenose dolphins can keep track of over 100 different words. They can also respond appropriately to commands in which the same words appear in a different order, understanding the difference between "bring the surfboard to the man" and "bring the man to the surfboard", for example.

But communication in most of these early experiments was one-way, says Denise Herzing, founder of the Wild Dolphin Project in Jupiter, Florida. "They create a system and expect the dolphins to learn it, and they do, but the dolphins are not empowered to use the system to request things from the humans," she says.